The only way the Bills would be in a position to move up for Rosen, would be for Darnold or Allen to go 1st overall, the Giants take Saquon Barkley at 2 and they trade up to 3 with Indy.
Even then, do you want this team, with all of its holes, to give up 2 firsts this year and possibly a 1st and 2nd in 2019 for Rosen?